This invention relates to electrically responsive display devices and in particular to a system for aligning a display device with respect to an external electrical circuit to effect electrical contact therebetween.
Various techniques are known in the art for aligning a display device such as liquid crystal display with an external electrical circuit such as a printed circuit board. Such techniques include bonding a piece of conductive film to the display; positioning the display within a casing of an electronic device such as an electronic calculator and fastening a printed circuit board to the casing so that the display is trapped in contact with the printed circuit board; and attaching the display to a plastic film material with the use of spring clips.
These and other prior art display systems have several disadvantages associated therewith. For example, it is difficult to maintain proper alignment and sufficient contact pressure between the display and the printed circuit board for reliable electrical contact therebetween. It is particularly difficult for large displays having high density conductive patterns formed thereon because generous alignment tolerances present in the system often lead to mismatch between the electrical contacts of the display and those of the printed circuit board. In addition, prior art display systems are not flexible enough to compensate for variations in display dimensions which occur among electronic devices. Further, display assembly is complicated by the fact that the display cannot be tested for proper operation until it is integrated into an end product such as a calculator system. Repair and/or replacement of the display and associated components is often difficult and inconvenient.